The present invention relates to a multi-specific antibody fusion protein which specifically recognizes the viral antigens (VA) HN or F surface antigen of the Newcastle Disease Virus (NDV), a surface molecule of a tumor-unspecific T cell, or a surface molecule of a dendritic cell and an immunocytokine. Also encompassed by the present invention are polynucleotides encoding the aforementioned antibody fusion protein as well as tumor-unspecific T cells or dendritic cells bound by the antibody fusion protein. Moreover, the present invention relates to a method of treating a tumor in a subject comprising administering to the said subject the antibody fusion protein, the tumor-unspecific T cell, the dendritic cell or the polynucleotide of the invention. Preferably, the said tumor is a solid tumor.
Various current cancer therapies aim to target specific compounds to the tumor cells. The targeted compounds may be cytotoxic compounds or compounds which serve as marker molecules for the immune system triggering an immune response against the tumor. In some cases linker molecules such as bispecific antibodies have been used for tumor-targeting. Such bispecific antibodies, usually, recognize a tumor-specific surface molecule and the compound or cell to be targeted to the tumor cell. Cells which have been successfully brought into contact to the tumor cells by the aforementioned targeting approaches are for example tumor-specific T cells, i.e. T cells recognizing a tumor antigen. It is envisaged that these tumor-specific T cells elicit an immune response against the tumor whereby the tumor cells are killed. More recent approaches aim to even enhance said effects of T cell targeting by using tumor-specific T cells which have been loaded by oncolytic viruses.
An interesting candidate virus to be used in human therapy of cancer is NDV. NDV is a member of the paramyxoviridae family. Virulent strains elicit avian pest in various bird species. In humans, the virus is, usually, not harmful and elicits, at most, weak inflammatory responses such as conjunctivitis or laryngitis (Csatary, 1999, Anticancer Res 19 (1B):635-8; Emergency Preparedness Information eXchange: Foreign Animal Diseases: Newcastle Disease. Burnaby, Canada: Telematics Research Lab, Simon Fraser University, 2002; Csatary, 1993, Cancer Detect Prey 17 (6):619-27; Kennedy, 1994, J Natl Cancer Inst 86 (16):1185-6; Kirn, 1996, Mol Med Today 2 (12):519-27; Lorence, 1994, J Natl Cancer Inst 86 (16):1228-33; Lorence, 1994, Cancer Res 54 (23):6017-21; Batliwalla, 1998, Mol Med 4 (12):783-94; Reichard, 1992, J Surg Res 52 (5):448-53; Schirrmacher, 1998, Semin Oncol 25 (6):677-96; Moss, 1996, J Naturopathic Med 6 (1):23-32). The NDV belongs into the family of lipid bi-layer containing viruses having a diameter of 150 to 300 nm. Its genome consists of 15 kb RNA of negative polarity. The genome comprises the following 6 genes (in 3″ to 5′ direction): nucleocapsid protein (NP, 55 kDa), phosphoprotein (P, 53 kDa), matrix protein (M, 40 kDa), fusion protein (F, 67 kDa), hemagglutinin-neuromimidase (HN, 74 kDa) and Large protein (L, 200 kDa) (Nagai 1998). The surface proteins HN and F are glycosylated transmembrane proteins. The matrix protein serves as an anchor for the genome and the genome-associated proteins NP, P and L, the latter ones forming the nucleocapsid of the NDV. The fusion protein (F) is also a glycoprotein which is synthesized as an inactive precursor (F0, 67 kDa) which is proteolytically cleaved into a biologically active protein consisting of two disulphide bond-linked chains (F1, 55 kDa and F2, 12.5 kDa) (Phillips, 1998). The cleavage sequence of the F protein and the length of the HN protein are the pivotal parameters responsible for the virulence of an NDV strain (Romer-Oberdorfer, 2003). Specifically, non-virulent NDV strains do not have cleavage sites in their F0 proteins. It has been recently found that NDV is capable of replicating in human neoplastic cells better than in non-neoplastic human cells (Pecora, 2002, Schirrmacher, 1999, Reichert, 1992). Accordingly, the virus is an interesting candidate for a virus-based anti-cancer therapy. Moreover, it has been found that the selective replication of the NDV is independent of the proliferation of the target cell population. Accordingly, even slowly growing cells can be efficiently infected (Schirrmacher, 1998). Since NDV is not harmful for humans and mechanisms of adaptation of NDV to the human immune system have not yet been described, there are no substantial concerns regarding the use of NDV for therapeutic purposes in humans (Schirrmacher, 2005).
More recently, a therapeutic approach has been described which combines virus-based therapy and targeting. In said approach, viruses are delivered to the tumor cells by tumor-specific T cells as a carrier. Specifically, tumor-specific T cells were obtained from a patient and were loaded ex vivo with intact virus. Subsequently, the loaded tumor-specific T cells were autologously administered to the patient where they delivered the virus to the site of the tumor. This approach is also known as “viral hitch-hiking”. (Cole, 2005, Nature Med 11 (10):1973-1081; Rooney, 2005, Nature Med 11 (10):1051-1052; Thorne, 2006, Science 311:1780-1784) This approach, thus, allows a targeted application of NDV rather than a mere systemic administration. However, the immune response induced against the tumor is still rather weak and inefficient as reported for the systemic administration. (Schirrmacher, 2001, Int J Oncol 18:945-952)
Accordingly, means and methods for an efficient and reliable immunotherapy of tumors and, in particular, solid tumors have no yet been described but are nevertheless highly desirable.
The technical problem underlying the present invention can be seen as the provision of means and methods for an efficient and reliable targeting based immunotherapy of cancer complying with the aforementioned needs. The technical problem is solved by the embodiments characterized in the claims and herein below.